1. Field of the Invention
The present invention relates to an organic light emitting display device and a method for fabricating the same capable of simplifying a fabrication process.
2. Discussion of the Related Art
For an image display device which embodies a variety of information on a screen as a core technology in advanced information and communication, there is continuous progress in development of thin, light-weight, and portable devices with improved performance. Hereupon, an Organic Light Emitting Display (OLED) device for controlling a luminescent amount of an organic luminescent layer is recently receiving attention as a flat panel display device, along with need of a flexible display capable of being bent pursuant to convenience and utilization of space.
The OLED device includes a Thin Film Transistor (TFT) array part formed on a substrate, an organic luminescent cell located on the TFT array part, and a glass cap to isolate the organic luminescent cell from the outside. The OLED device applies an electric field to a cathode and anode formed at both ends of an organic luminescent layer so as to inject and transfer electrons and holes into the organic luminescent layer, thereby utilizing an electroluminescence phenomenon which emits light by bonding energy during combination of the electrons and holes. The electrons and holes, which are paired with each other in the organic luminescent layer, emit light while falling from an excited state to a ground state.
In detail, the OLED device includes a plurality of sub-pixels arranged at a pixel region defined by intersection of a gate line and a data line. Each of the sub-pixels receives a data signal from the data line when a gate pulse is supplied to the gate line, thereby generating light corresponding to the data signal. In this case, each sub-pixel includes a TFT formed on the substrate and an organic luminescent cell connected to the TFT.
FIG. 1 is a sectional view illustrating a conventional OLED device. The following description will be given of a method for fabricating the conventional OLED device with reference to FIG. 1.
As shown in FIG. 1, the conventional OLED device includes a TFT formed on a substrate 10, and an organic luminescent cell connected to the TFT while including a first electrode 18, an organic luminescent layer (not shown), and a second electrode (not shown) formed on the organic luminescent layer.
On the substrate 10, a light shield layer 11 is formed using a first mask and a buffer layer 12 is formed to cover the light shield layer 11. An oxide semiconductor layer 13 is formed on the buffer layer 12 using a second mask, and a gate insulation film 14 and gate electrode 14a are deposited in turn on the oxide semiconductor layer 13 using a third mask.
The oxide semiconductor layer 13 is exposed, at both edges thereof, by an interlayer insulation film 15 formed to cover the gate electrode 14a using a fourth mask. Source electrode 16a and drain electrode 16b are formed to be respectively connected to both the exposed edges of the oxide semiconductor layer 13, using a fifth mask. The drain electrode 16b is exposed by a protective film 17 formed on the interlayer insulation film 15 using a sixth mask.
The exposed drain electrode 16b is connected to the first electrode 18 formed on the protective film 17 using a seventh mask, and a bank insulation film 19 is formed on the first electrode 18 using an eighth mask so as to define a luminescent region and non-luminescent region of each sub-pixel. Although not shown, on the exposed first electrode 18, the organic luminescent layer is formed and the second electrode is further formed to cover the organic luminescent layer.
That is, the conventional OLED device as described above is fabricated using eighth masks up to formation of the bank insulation film 19, thereby increasing fabrication costs and process time.